//To create Figure 1, use the following code:

graph box groups if complete==1, over(year)

//To generate descriptive statistics for covariate observations from the complete panels only, use the following code:

sum varname if complete == 1, det

//This code is first required for executing xt commands in Stata with panel data:

xtset state year

//To calculate results from model 1 in Table 3, use the following code:

xtnbreg groups  realgsp000000 realgsp2000000 prof_preceding initiativestate definitions prohibitions reports defpro defrep

//Results from model 2 in Table 3:

xtnbreg groups  realgsp000000 realgsp2000000 prof_preceding foldedranney6yr initiativestate definitions prohibitions reports defpro defrep

//Results from model 3 in Table 3:

xtnbreg groups  realgsp000000 realgsp2000000 prof_preceding initiativestate definitions prohibitions reports defpro defrep if complete==1

//Results from model 4 in Table 3:

xtnbreg groups  realgsp000000 realgsp2000000 prof_preceding  foldedranney6yr initiativestate definitions prohibitions reports defpro defrep if complete==1

//Results from model 5 in Table 4:

reg groups  realgsp000000 realgsp2000000 prof_preceding  initiativestate definitions prohibitions reports defpro defrep i.fips i.year

//Results from model 6 in Table 4:

reg groups  realgsp000000 realgsp2000000 prof_preceding  foldedranney6yr initiativestate definitions prohibitions reports defpro defrep i.fips i.year

//Results from model 7 in Table 4:

reg groups  realgsp000000 realgsp2000000 prof_preceding  initiativestate definitions prohibitions reports defpro defrep i.fips i.year if complete==1

//Results from model 8 in Table 4:

reg groups  realgsp000000 realgsp2000000 prof_preceding foldedranney6yr initiativestate definitions prohibitions reports defpro defrep i.fips i.year if complete==1

